2Department of Physics and Astronomy, Free University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands, and Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627

3Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and The Institute of Optics, University of Rochester, Rochester, New York 14627

Abstract

We analyze the coherence properties of a partially coherent optical field emerging from two pinholes in a plane opaque screen. We show that at certain pairs of points in the region of superposition the light is fully coherent, regardless of the state of coherence of the light at the pinholes. In particular, this result also holds if each pinhole is illuminated by a different laser.